21. A beam of electrons is directed into the electric field between two oppositely charged parallel plates, as shown in the diagram below.

The electrostatic force exerted on the electrons by the electric field is directed

(1) into the page(2) out of the page(3) toward the bottom of the page(4) toward the top of the page

22. When two ring magnets are placed on a pencil, magnet A remains suspended above magnet B, as shown below.

Which statement describes the gravitational force and the magnetic force acting on magnet A due to magnet B?

(1) The gravitational force is attractive and the magnetic force is repulsive.(2) The gravitational force is repulsive and the magnetic force is attractive.(3) Both the gravitational force and the magnetic force are attractive.(4) Both the gravitational force and the magnetic force are repulsive.

23. Which color of light has a wavelength of 5.0 × 10–7 meter in air?

(1) blue(2) green(3) orange(4) violet

24. Which type of wave requires a material medium through which to travel?

(1) sound(2) radio(3) television(4) x-ray

25. A periodic wave is produced by a vibrating tuning fork. The amplitude of the wave would be greater if the tuning fork were

26. The sound wave produced by a trumpet has a frequency of 440 hertz. What is the distance between successive compressions in this sound wave as it travels through air at STP?

(1) 1.5 × 10–6 m(2) 0.75 m(3) 1.3 m(4) 6.8 × 105 m

27. The diagram below represents a light ray striking the boundary between air and glass.

What would be the angle between this light ray and its reflected ray?

(1) 30.°(2) 60.°(3) 120.°(4) 150.°

28. In which way does blue light change as it travels from diamond into crown glass?

(1) Its frequency decreases.(2) Its frequency increases.(3) Its speed decreases.(4) Its speed increases.

29. The diagram below shows two pulses approaching each other in a uniform medium.

Which diagram best represents the superposition of the two pulses?

30. Sound waves strike a glass and cause it to shatter. This phenomenon illustrates

(1) resonance(2) refraction(3) reflection(4) diffraction

31. An alpha particle consists of two protons and two neutrons. What is the charge of an alpha particle?

(1) 1.25 × 1019 C(2) 2.00 C(3) 6.40 × 10–19 C(4) 3.20 × 10–19 C

32. An electron in the c level of a mercury atom returns to the ground state. Which photon energy could not be emitted by the atom during this process?

(1) 0.22 eV(2) 4.64 eV(3) 4.86 eV(4) 5.43 eV

33. Which phenomenon provides evidence that light has a wave nature?

(1) emission of light from an energy-level transition in a hydrogen atom(2) diffraction of light passing through a narrow opening(3) absorption of light by a black sheet of paper(4) reflection of light from a mirror

34. When Earth and the Moon are separated by a distance of 3.84 × 108 meters, the magnitude of the gravitational force of attraction between them is 2.0 × 1020 newtons. What would be the magnitude of this gravitational force of attraction if Earth and the Moon were separated by a distance of 1.92 × 108 meters?

36. The work done in lifting an apple one meter near Earth’s surface is approximately

(1) 1 J(2) 0.01 J(3) 100 J(4) 1000 J

Refer to the following information for the next two questions.

Base your answers to questions 37 and 38 on the graph below, which represents the motion of a car during a 6.0-second time interval.

37. What is the acceleration of the car at t = 5.0 seconds?

(1) 0.0 m/s2(2) 2.0 m/s2(3) 2.5 m/s2(4) 10. m/s2

38. What is the total distance traveled by the car during this 6.0-second interval?

(1) 10. m(2) 20. m(3) 40. m(4) 60. m

39. A person weighing 785 newtons on the surface of Earth would weigh 298 newtons on the surface of Mars. What is the magnitude of the gravitational field strength on the surface of Mars?

(1) 2.63 N/kg(2) 3.72 N/kg(3) 6.09 N/kg(4) 9.81 N/kg

40. A motorcycle being driven on a dirt path hits a rock. Its 60.-kilogram cyclist is projected over the handlebars at 20. meters per second into a haystack. If the cyclist is brought to rest in 0.50 second, the magnitude of the average force exerted on the cyclist by the haystack is